Remote monitoring systems may use direct transmission lines, such as standard telephone lines to transmit signals indicating conditions of a device, equipment, or object to be monitored. Standard telephone lines can transmit a voice frequency from 300 Hz to 3000 Hz. To monitor and transmit signals outside this range using the standard telephone lines, special means are incorporated to convert the signals and transmit the converted signals via the telephone lines. Upon receipt of the converted signals, the converted signals are converted back for further analysis. Due to the bandwidth limitation of the normal telephony, the signals received may be different from those of the original transmitted pattern. Furthermore, the direct transmission of data using these lines is cost prohibitive in many circumstances as the location of the device may be in remote locations. Moreover, the direct telephone lines may require servicing, as the lines may be damaged by weather or the passage of time. Because of such degradation, the conditions of the device, equipment or object may not be accurately monitored.
An alternative means of monitoring devices is manual inspection. Manual inspection requires a person to physically visit the location of the device being monitored. For example, when monitoring the condition of power lines, or components thereof, such as insulators, the person monitoring the condition must visit each insulator individually. As the cost of a man hour increases, monitoring the status of remotely located devices will also increase.
Thus, there exists a need for a remote monitoring system which does not require direct telephone lines connected to a device being monitored and does not require a person to visit the site of the device to monitor the condition of the device.